.section .data 
msg:
    .ascii "hello world\n"
    len=.-msg 
 
.section .text
# .global main
# main:
.global _start
 
_start:
movl $len, %edx 
movl $msg, %ecx
movl $1, %ebx 
movl $4, %eax
int $0x80   
 
movl $0, %ebx 
movl $1, %eax
int $0x80   

